New to DVD burner, need a bit of advice please

[belveder]

I just bought a Pioneer DVR 106D burner and am a little confused about something.

I have burnt a few avi's using Nero with no problems using normal disc's before but what do I do now if I burn a vcd from an avi onto a DVD disc?

How do I change the size of the disc to the right size etc. I presume now that I could fit a couple vcd's onto one disc and make some sort of a menu, or is that not right?

Any advice would be appreciated.

Thanks